Effects of solute-matrix interaction on monitoring the conformational changes of immobilized proteins by surface plasmon resonance sensor

A real-time and labeling-free surface plasmon resonance (SPR) sensor was used to monitor the conformational changes of immobilized globule proteins (RNase A and lysozyme) in chemical unfolding and refolding. The effects of chemical denaturants on the protein structures were investigated. The methodology in protein conformational study on the solid surface is refined through the theoretic calculations and the conformational information of native/denatured proteins in solution. Additionally, our observation illustrates that the ambient buffer solution is merit to influence the refractive index of immobilized protein films and directly be observed from the SPR resonance angle shifts.     

Productive public expenditures, expectation formations and nonlinear dynamics

In this paper, we investigate the dynamic properties of an overlapping generations’ model with capital accumulation and publicly funded inventions under three different expectations: perfect foresight, myopic expectations and adaptive expectations. We show that considering productive public expenditures in the model will increase the dimension of the dynamical system. To study the dynamic behavior of a high-dimensional dynamical system, we focus on the case when the elasticity of publicly funded invention to output is small and approximate the system by using a one-dimensional dynamical system. This approximation method provides an efficient way to rigorously prove the existence of chaos in high-dimensional dynamical systems. We show that when agents are perfectly foresighted, there exists a unique, nontrivial steady state which is a global attractor. Cycles or even chaos may occur under myopic and adaptive expectations when the inter-temporal elasticity of substitution of consumption is large enough. Furthermore, we find that the impact of fiscal policy is sensible to the expectation formation.     

Human capital externality and chaotic equilibrium dynamics

This study develops a two-period overlapping generations model in which adults undertake educational investment decisions on behalf of young agents. In addition to educational investment, we argue that the accumulation of human capital is also dependent upon the externality from average human capital within the economy. In a departure from the previous literature in this area, we assume that there is a reduction in the overall productivity of human capital accumulation brought about by human capital externality, and show that complicated dynamics will emerge under this circumstance. In addition to displaying the chaotic dynamics in the sense of Li and Yorke, we also verify the existence of Devaney's chaos and Smale's chaos.     

A simple proof for persistence of snap-back repellers

In this article, we show that if f has a snap-back repeller then any small C¹ perturbation of f has a snap-back repeller, and hence has Li-Yorke chaos and positive topological entropy, by simply using the implicit function theorem. We also give some examples.     

Synchronized dual-polarity electrospray ionization mass spectrometry

This work describes the synchronized dual-polarity (DP) electrospray ionization (ESI) method and demonstrates the first DP ESI mass spectra obtained using two mass spectrometers. Stable double Taylor cones were produced by applying two counter electric voltages with opposite polarities to one electrosprayer. The development of double Taylor cones required higher extraction voltages than conventional ESI, but DP ESI worked effectively at liquid flow rate range three times wider than conventional ESI. Using pure methanol, the emission currents of the two cones were neutralized and no current was drawn from the sprayer. Synchronized DP mass spectra were obtained using electrospray calibrants dissolved in methanol solution of low water content. For bovine insulin with conventional electrospray solution, the gas-assisted electrospray delivered satisfactory sensitivity and stability for routine mass analyses.     

Approximation of entropy on hyperbolic sets for one-dimensional maps and their multidimensional perturbations

We consider piecewise monotone (not necessarily, strictly) piecewise C ² maps on the interval with positive topological entropy. For such a map f we prove that its topological entropy h _top(f) can be approximated (with any required accuracy) by restriction on a compact strictly f-invariant hyperbolic set disjoint from some neighborhood of prescribed set consisting of periodic attractors, nonhyperbolic intervals and endpoints of monotonicity intervals. By using this result we are able to generalize main theorem from [1] on chaotic behavior of multidimensional perturbations of solutions for difference equations which depend on two variables at nonperturbed value of parameter.     

Structural stability on basins for numerical methods

In this paper, we show that a flow with a hyperbolic compact attracting set is structurally stable on the basin of attraction with respect to numerical methods. The result is a generalized version of earlier results by Garay, Li, Pugh, and Shub. The proof relies heavily on the usual invariant manifold theory elaborated by Hirsch, Pugh, and Shub (1977), and by Robinson (1976).

     

Angular dependence of OH degenerate four-wave mixing signals in a flame

The dependencies of line intensity and linewidth of degenerate four wave mixing (DFWM) on the crossing angle have been investigated via OH A²Σ − X²Π transitions in a flame. The measured results were compared with the theoretical predictions and other experimental results. It was found that the saturation effect was important and must be considered. When using the DFWM method to measure the temperature, a suitable crossing angle should be chosen and the absorption correction should be taken into account.     

Habit formation and chaotic dynamics in an n-dimensional cash-in-advance economy

This paper investigates the global dynamics of an n-dimensional cash-in-advance model where external habits persist for n periods. We find that habit formation is an important determinant to the dynamic property of the economy and identifies conditions generating entropic chaos. Our results indicate that the possibility of chaotic motion increases with the depreciation rate of habits.